In April 2026, one of the major projects in the Solana DeFi ecosystem lost approximately $285 million. At first glance, it seems like a "network hack," but the real issue was in the protocol's architecture and transaction execution logic, not the blockchain's security.
The core of the incident: the attacker used pre-signed transactions and access to multisig wallets, as well as delayed execution mechanisms. The transactions were valid, signed by trusted parties, but executed later when conditions became favorable for the attacker.
Simple example of a Solana transaction in JavaScript:
A feature of Solana is the ability to use a durable nonce, which allows a transaction to remain valid longer than the standard blockhash. This allows signing now and executing later:
The problem was not in cryptography, but in how the protocol logic and trust in users were structured. The combination of pre-signed transactions, trust in multisig, and the lack of real-time system state checks allowed the attacker to withdraw funds in minutes.
Key Developer Mistakes
- Lack of state check before execution — the system did not account for condition changes since the transaction was signed.
- Excessive trust in signed transactions — signing does not always imply consent to current conditions.
- Weak access segmentation — multisig wallets do not guarantee security during automated execution.
- Lack of risk monitoring — collateral state, liquidity, and other parameters must be checked before execute.
Conclusions for Developers and Security Teams
- Always check the system state before executing transactions.
- Don't trust blind transactions, even if signed by trusted parties.
- Implement access segmentation and permission control at the architectural level.
- Use real-time monitoring and additional checks before key actions.
Even in 2026, DeFi attacks are not just brute-force or cryptographic errors. Most incidents involve exploitation of protocol logic and human behavior, using the system's mechanisms against itself.
Understanding such cases is crucial for all developers and security professionals working with blockchains, smart contracts, and financial dApps.